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Collecting Data to Determine Baked Loaf by Weight

Collecting Data to Determine Baked Loaf by Weight

Calling any Fresh Loafers to join in an experiment to collect data to determine when a loaf is finished baking by using a little math and weighing the loaf pre and post bake.

I've heard, read and used a few different ways to determine when a loaf is done. Loaf temperature, thump, squeeze, time. Jeff Hamelman and a few others say a loaf can lose between 10 ~ 20% moisture during the bake. If I attempted to do this myself it could take awhile so I'm asking others to join in and post their results along with mine.

It isn't always so simple for some people. I think the findings may prove interesting. It may be a more accurate than a thermo or a thump. If you're trying out a new shape or formula and end up with a wet crumb it may help to start weighing the results. When baking in a different or new oven it may help.

Do you have a model of what the end result will look like, and the intended route by which you will get there?

There will probably be significant factors that scale with loaf weight and final crumb temperature, which you are not asking for as part of the data collection.

I suggest you include them so that you have what you will no doubt eventually need to determine the eigen vectors of all the multivariate data. The result should be a functional relationship rather than a number.

There is also no measure of "over-" or "under-" doneness which is what you are trying to tease out as a function of weight loss, so the assumption has to be that every data point is pulled from the oven at the Goldilocks point.

Guess I should have asked for your advice before the posting. My thoughts were that the participant would weight loaves they were familiar with and happy with the results. If they had variants of success the % moisture loss could be another tool.

Was hoping the results would be something like an average boule would lose 15% and a batard 17% and so on. I was avoiding the loaf temp since I was trying to use the weights as an alternative test. I have no idea concerning eigen vectors and multivariate data.

I'm not sure I've answered all your concerns yet I would ask, If you think this is a worthwhile test, to add additional parameters and assist in the test. A joint venture so to speak.

When I bake my 75% hydration baguettes they go in the ovens at 470g and come out at 360-370g, so if my calculations are correct, they lose between 23.4% and 21.3% of their water. When I make them as half-size baguettes (half in length, but the same width), they lose the same ratio of water.

As I see it, this is an exercise in futility. The difference in weight of a finished loaf at (for example) 200 degrees vs 205 degrees is going to be extremely difficult to measure with the typical baker's scale. I suspect you'll need a scale with microgram capabilities, or better. Nevertheless, best of luck.

You are losing moisture at about 0.5 to 1.0%/min of baking time, and the difference between 200°F and 205°F is about a minute for a 600g loaf. So the potential difference is 3-6g which is certainly measurable. Whether it is significant is another question.

I found some information (bottom left paragraph p. 208) Giving an example for a white wheat loaf 800g loaf water 60.7% hydration with oven loss of 65g being used for figuring energy use. The document reads like a textbook and everything you ever wanted to know about bread included. Title of the book is "Technology of Cereals" by Kent. The link opens on Chapter(?) 8. After combing thruTHIS LINK I'm tempted to post it separately under. "Information if you ever wanted to know." It seems written from a UK point of view and covers so many facts. It certainly is comprehensive.

It seems we are trying to find an accurate indicator of doneness. Your implied hypothesis seems to be that weight loss is a proxy and you have in your head a model of how one might set up some way to trigger a "done flag" when a loaf has lost the appropriate amount of weight.

In trying to think through what "done" means in a bread context there would seem to be some water absorption, some protein activity, some starch involvement, some structure formation that probably involves all of these, and it is facilitated by temperature. Since I have not done the reading necessary to fully understand what "done" means, I am at a loss for suggesting how to measure it.

My suggestions for data collection were simply an attempt to make sure that you collect enough information to be able to model what is going on and avoid the common experimental conundrum of discovering late in the process that you didn't record the right variables. There are a bunch of 6-sigma training exercises where the students model some process and look for the sources of variation. Inevitably they do not understand what is going on when they start so they measure what is "obvious" rather than what they can or will eventually need to know to control the experimental outcome. Your two parameter model will converge, but with a large standard deviation, the source of which probably lies in unmeasured variables. But progress comes with iteration and in this case it also means a substantial amount of rework.

Good luck. I am going to watch, but probably not contribute. I don't make straight dough loaves (freestanding or panned) so there is no place for my data to get into your analysis.

Thanks for your input! Looks like I'm trying to get from Point A to Point B yet am unsure of the path. And if I don't start somewhere ~ I'll get nowhere.

When I wrote straight dough I only meant un-enriched, no additives such as fats, nuts, sweeteners or milk. Any preferment would be okay. Myself, 90% of what I bake is about half sourdough and half assorted preferment's.

Defining my outcome as "a tool to adjust for a wet crumb", without getting too complicated, what data collection would you suggest as a starting point? By using the data suggested so far differences observed/measured between similar loaves may give an indication of whether or not, or to what degree, water absorption, some protein activity or some starch involvement have an effect. Then new parameters could be defined?

....trying to find ways to quantify the characteristics in breads. Jim in particular wonders if moisture loss correlates to doneness. That's worth pursuing in my opinion.

We talk about...this loaf is dense and that loaf is moist and this dough is extensible while that dough is elastic. But, how dense, how moist, how extensible and how elastic aren't defined for the home baker. So...we are trying to develop some reliable tests for the kitchen. Most bakers wouldn't be interested, but the "geekier" of us might be interested.

I was somewhat surprised to find that the Schrotbrot I baked in a sealed Pullman Pan went from a spoon-able paste at 1550 grams to a finished 1350 grams after a 4 hour bake. 1:15 at 350F and the balance at 240F. The pan was covered with foil and the lid applied but the steam must have carried the water away, all 200 grams of it. Something like 13% loss. The bread is remarkably good BTW.

Do you have any sense yet of whether measuring water loss by measuring weight will indicate doneness better than the old thump test or the crumb temperature measurement?

(My own guess is that it will turn out that measuring water loss can be useful for one baker with the same oven using the same recipe to bake loaves "exactly the same as last time", but won't be useful for transferring a procedure/recipe from BakerA to BakerB ...however I know that quite often my guesses turn out to be flat wrong and I get surprised. My own experience has been that [warning: sacrilege ahead:-] although tests like the crumb temperature test are very useful when exploring, once I've got a loaf "right", when I bake the same recipe in the same size and shape again, there's nothing better than the clock on the wall to bake it "the same". It seems you don't really have enough data yet to draw any firm conclusions, but do you at least have a "sense" of which way the wind is blowing?)

(Also keep in mind that the internal temperature test might not be such a great thing to compare against. Although it's probably the best we currently have, it's been discussed here on TFL that it's not at all accurate too close to 210F, and needs to be supplemented with other measures.)

My sense of what's blowin' in the wind is the data collected could provide us with another tool. Or the weight loss measurement a tool in and of itself. And I love tools; you should see my workshop. As you say this would be of most use for the individual home baker to zero in on the perfect bake. A tool to use to avoid the dreaded wet loaf. I don't think this will set a standard weight to bake to, per se. Some of my reasoning for doing this test is the info I've collected and pasted below. Sorry I didn't copy the person who posted the first statement, yet I believe it was from a professional bakers post on the Bread Bakers Guild of America Yahoo Group.

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Water -- pure water -- boils at 212°F, at sea level. Water that is bonded to proteins, starches and other dough ingredients by electrostatic forces no longer has the boiling characteristics of pure water, and -- because energy is required to break those bonds -- boils at a higher temperature than pure water.--------------------------------------------Merely plunging a thermometer into the nether regions of a poor loaf will give you some objective information. And beyond that, there are some other, more subtle aspects of the bake that should be considered as well. One thing you might try is the following: when you are taking bread out of your oven at home, give it a good squeeze, top and bottom, and get a sense of how much pressure you have to exert before the bread gives a bit of a crack (just tapping the top of the loaf tells you nothing, as that part got hard pretty early in the bake-you do need to do a full squeeze). Then take the temperature. When the bread is cool and you eat it, you can now tell for sure if it is baked to your liking. If it is, then try to get a tactile imprint on what it felt like when you squeezed it. Keep doing that squeeze and thermometer testing for several bakes. Slowly you will begin to trust what your hands are feeling, and I guarantee that they will soon pick up enough sensitivity to know doneness.Jeffrey Hamelman, Bakery Director, Certified Master Baker, BBGA Yahoo 2/11/06

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If a baker goes to all the work of developing the loaf up to the point of baking why not use every tool at hand to turn out a great loaf? As I stated in a different post "Oven temperature sets the crust; length of bake sets the crumb". Weighing the loaf could help to determine length of bake.

I'm slightly with Michael in the first reply to your post. Breadmaking is a simple everyday activity, it's true - and yet you can make it fiendishly complicated if that's your wish.

I'm not sure it's possible to use the weight of a loaf to see if it is done, as there are too many variables - and there are easier ways of checking, IMO.

When I worked in a bakery for a brief period in the nineties (as a breadmaking tutor I was curious about what went on in bakeries), we would scale the dough at 2lb and finish up with a loaf weighing 1lb 12oz. So:

1. 12.5%

2. Tinned loaf

3. 62.5% hydration

Incidentally, when the law changed and the baker had to convert to metric, he scaled his dough at 1 kilo. His loaves then weighed around 900g after baking - when they only had to (by law) weigh 800g. I could not persuade him he was giving away 100g of bread with every loaf - I was an amateur in his eyes, and therefore didn't know anything!

I bake my bread (as rolls, for convenience) undercover, to this recipe and method:

And I scale my rolls off in pairs - I weigh 224g of dough, divide it in two and shape the rolls. So each roll should weigh 112g.

I've just hauled half a dozen rolls out of the freezer and weighed them. To my surprise they range from 86g to 102g - averaging 95g each. So:

1. 15.1%

2. Undercover rolls

3. 70%

The difference in the two types of bread is almost entirely down to the sizes of the breads. Of course a roll will have a greater crust to crumb ratio than a loaf.

And that's just one variable!

But good luck with your quest - I shall be watching with interest.

(BTW, I'm surprised at the variation in weight between my rolls. Next time I'll weigh them individually - and check the position in the oven against the finished weight. Obviously the ones in the middle will lose more moisture than the ones at the corners. I'll report back on this.)

Best wishes, Paul

Ps. Just remembered I include 5g of ground flaxseeds in each roll - so not a 'straight' dough. :(

Aha! You've encountered the first thing that's got me wondering. My last bake of 2 boules lost 20g between initial scaling of ingredients and pre-bake weight. I find it hard to believe that 20g was left in the mixing bowl and on the dough hook. Your rolls decreased in weight after freezing; more moisture loss? I've gone so far as to exactly scale two loaves only to find a difference of 6g between them after proofing. Why?

As you pointed out the weight of a finished loaf may need to be of a certain weight. As a member of the Bread Bakers Guild of America I've read a few posts where bakers have been fined big dollars for loaves that didn't meet minimum weight.

Baking can be as simple or as complex as one wishes it to be. I don't think weighing the loaf pre and post bake is complicated. And the math is no more complicated than Bakers Math. As you say there will be variables and it will be interesting to see what they may be. There is tons of information about the wild yeast and bacteria, and I've read a bit of it. Yet science and practical application are two different animals.

What could be better than bringing a fresh baked loaf to a family gathering? Maybe bring the loaves to bake at the gathering and fill the home with those wonderful aromas. Armed with a thermo and a scale it may be easier to bake the loaves to perfection in an unfamiliar oven.

Since there is no way to establish when my loaf is "Done" to the satisfaction of a standard, before removing from the oven, of what value is knowing what the moisture loss is? You would need to know how long it took and at what altitude the baking took place for any of this to make sense. We can measure time and temperature but we live by the laws of physics as to the effect of pressure on boiling water.

Baking is all about the crust and crumb. It would be interesting to see how altitude effects the outcome of the data and would be interested in any data you could contribute. It is easy to postulate what variable could exist and attempting to collect some data is all I'm attempting to do at this point. I'm like that Newton guy; I'm gonna stand under the apple tree till something happens and then figure out why.

There have been posts here referring to wet loaves and as I remember a few had to do with Dutch Ovens/Combo Cookers and Tartine. The bakers were baking to temp yet the loaves were wet. Could scaling have helped them? If scaling is used as a reference the loaves could go back into the oven.

This leads me to thinking, does how soon the crust forms relate to moisture loss? In my baking I usually remove the cover (cloche et al), vent the oven and lower the temperature after the crust forms, usually 15 mins. Then finish the bake. Will varying this procedure after moisture loss? I'd like to know.

In the end the outcome may be a combo of temp and weight may be more accurate.

I have had loaves develop a good color crust and look done but blow steam when I checked the temp and pulled the probe. The loaf was pressurized. Good gluten development, effective shaping and tightening come into play in this scenario. Not to mention slashing depth.

And did the pressurized loaf give a 200°F+ reading? I agree every step of the process, from the point of dough meets water, has an effect on the outcome. I'm going to do some tests to see if lowering the initial oven temp will have an effect on moisture loss.

Other reading; from "The Bread Builders", Wing & Scott. pg. 93, "In fact, dough only loses 12% of it's weight as it is baked. What turns dough into bread is an amazing chain of physical events and chemical transformations, most of which involve shifts in water within the dough."

I need more data to begin to come to any conclusions. Yet so far I do find the results interesting. I was hoping others would post some results. As always I'm doing slight variations in technique to every dough I'm using and continue researching bread information. Have you any weight loss data to add?

I feel say to say with my set-up, others may vary, at 68% hydration with less than 10% other than AP flour, with a pre-ferment, at an altitude of about 700 ft above sea level, with a starting loaf weight between 650 & 750g's; After a bake time of 35 t0 40 mins (initial oven temp 450°F lowered to 400°F after 5 mins ) to achieve desired crust color, 8 to 9% weight loss, after 15 additional min. with oven turned off and door open 6 inches, another 1.5 to 2% and after a 1 hour room temperature cool down, another 1.5 to 2% loss.

The end result was 14.85 in total. I missed to weigh each portion after preshaping... oops.

The dough has gone through a 3 laps of Stretch and Fold with 15 minutes gap. then through 19 hours in the fridge. I have preshaped the dough, for small baguette, directly out of the fridge and left the portions to rest for 1 hour before final shaping and final rise. After the final rise, baked in hearth oven under 500F degree, finally out of the oven, cooled and then in my belly :)

I have attached some photos....

the texture is lovely, so flaky from outside and soft from the inside... and guess what, for the first time is very light.

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